Polyisobutylenes (PIBs) having two terminal functional groups are desirable and valuable intermediates for the preparation of a great variety of end products. For example, the di-hydroxyl telechelic PIB (HO-PIB-OH) and the di-amine telechelic PIB (NH2-PIB-NH2) are key ingredients for the preparation of the soft segment of hydrolytically-oxidatively resistant PIB-based polyurethanes and polyureas, respectively.
Methods for the preparation of some HO-PIB-OH compounds are well known in the art and, in some cases, have been patented. For example, primary alcohol-terminated PIB compounds have been produced from vinylidene groups or from allyl groups. Further, the use of these particular patented HO-PIB-OH compounds for the preparation of polyurethanes has also be described. It will be appreciated that “hydroxyl-terminated” and “alcohol-terminated” are used interchangeably.
However, the production of these primary alcohol-terminated PIB compounds, such as HOCH2-PIB-CH2OH, have been prepared in the past using various synthesis methods that are, to say the least, cumbersome and uneconomical. For instance, one example of the production of primary alcohol-terminated PIBs requires the use of expensive boron chemicals and related complexes through the use of a hydroboration/oxidation process. Alternatively, the allyl-terminated PIBs and vinylidene-terminated PIBs may undergo bromination via any of a number of known techniques, including anti-Markovnikov addition, and then be converted to the hydroxyl-terminated PIBs by nucleophilic substitution of the bromine. Again, such processes require costly, aggressive and expensive chemicals such as bromine, and as such, the cost of manufacturing primary alcohol-terminated PIB compounds has been, in some respects, too high for commercial production.
Given the above, numerous efforts have been made to develop a more simple and economical process for the manufacture of primary alcohol-terminated PIB compounds, HO-PIB-OH. The polyurethane industry alone has spent millions of dollars on the research and development of various processes for the manufacture of HO-PIB-OHs. Heretofore, such efforts have bee met with only limited success in reducing the cost associated with producing primary alcohol-terminated PIB compounds.
Accordingly, the need exists for a more efficient and more economical process for the production of primary alcohol-terminated PIBs that can then be used in the production of polyurethanes and other materials.